Deinking agent

ABSTRACT

Provided is a deinking agent making it possible to improve ink collecting power in the step of flotation and yield high-quality deinked pulp without lowering the yield of pulp. It is a deinking agent comprising an ester of an alkylene oxide-added product of glycerin, its hydroxyl value (OHV), saponification value (SV) and acid value (AV) satisfying the following: OHV/(SV−AV+OHV) ranges from 0 to 0.3.

TECHNICAL FIELD

[0001] The present invention relates to a deinking agent.

PRIOR ART

[0002] Importance has been increasingly attached to effective use of waste paper in connection with global environment problems such as protection of forest resources and waster disposal. When deinked pulp, which is regenerated from waster paper, is used to attain a high blend ratio thereof, it is necessary to obtain higher-quality deinked pulp, that is, deinked pulp wherein the amount of residual ink is small. For deinking, it is necessary to perform effectively deinking for releasing ink from paper and ink removal for separating the released ink from pulp. About deinking agents, it has been desired to develop deinking agents and ink removing methods which are good in ink releasing property and ink collecting property. As deinking agents, there have been developed a reaction product wherein an alkylene oxide (referred to as an AO hereinafter) is added to a mixture of oil and fat and an alcohol (for example, Japanese Patent No. 1573380), a reaction product wherein an AO is added to an aliphatic acid (for example, Japanese Patent No. 2645208), a reaction product wherein an AO is added to a higher alcohol (for example, Japanese Patent Nos. 2999363 and 3081120), and others. The higher alcohol AO-added product is used as a deinking agent superior in economy and multiusability.

DISCLOSURE OF THE INVENTION

[0003] However, the higher alcohol AO-added product has superior ink releasing property, but has strong ink dispersing power so as to be poor in ink collecting property. In order to obtain deinked pulp having a high quality, that is, having a little remaining ink, there are measures for using an ink collecting agent, such as an aliphatic acid, together in flotation step and steps previous thereto in order to compensate for ink collecting property; or for allowing a fall in the yield of pulp so as to increase foaming property in flotation step, thereby increasing discharged-froth amount. However, these measures have problems from the viewpoints of workability, facilities, and costs since additional treatment is conducted. It is therefore desired that the performance of deinking agents themselves is made better.

[0004] The invention provides a deinking agent comprising a compound represented by the following general formula (Y), its hydroxyl value (OHV), saponification value (SV) and acid value (AV) satisfying the following: OHV/(SV−AV+OHV) ranges from 0 to 0.3.

X—[O-(AO)m-R)n   (Y)

[0005] [wherein R is each independently a hydrogen atom or an acyl group having 1 to 24 carbon atoms, provided that at least one of plural R is an acyl group having 8 to 24 carbon atoms, A is an alkylene group having 2 to 4 carbon atoms, A may be the groups wherein the numbers of their carbon atoms are different, and m×n is a numerical number of from 45 to 1000, X is a polyhydric alcohol group, n is a number of 3 to 10 being equivalent the valence of X.

[0006] The term “polyhydric alcohol group” means a residue derived from a polyhydric alcohol by removing hydrogen atoms from alcohokic hydroxy groups thereof.

[0007] The present invention relates to a deinking agent comprising a compound represented by the following general formula (a), its hydroxyl value (OHV), saponification value (SV) and acid value (AV) satisfying the following: OHV/(SV−AV+OHV) ranges from 0 to 0.3.

[0008] [wherein R¹ to R³ are each independently a hydrogen atom, or an acyl group having 1 to 24 carbon atoms provided that at least one of R¹ to R³ is an acyl group having 8 to 24 carbon atoms, A is an alkylene group having 2 to 4 carbon atoms, A may be the groups wherein the numbers of their carbon atoms are different, and a+b+c is a numerical number of from 45 to 1000, preferably from 70 to 1000.]

[0009] The present invention also relates to a deinking agent comprising a compound represented by the general formula (a), the hydroxyl value (OHV) of a fraction having a weight average molecular weight of 2000 or more, the saponification value (SV) thereof and the acid value (AV) thereof satisfying the following: OHV/(SV−AV+OHV) ranges from 0 to 0.3.

[0010] The present invention also relates to an ink removing method of using the deinking agent of the present invention in an ink removing step.

[0011] The invention provides a process for preparing a deinking agent comprising a compound represented by the general formula (Y) as defined above and having the value of OHV/ (SV−AV+OHV) in the ranges of from 0 to 0.3 wherein hydroxyl value (OHV), saponification value (SV) and acid value (AV), comprising the step of esterifying an alkylene oxide adduct to a polyhydric alcohol having 3 to 10 valences or a mixture of a polyhydric alcohol having 3 to 10 valences with fats and/or oils with a carboxylic acid at a temperature of 100° C. to 260° C.

[0012] The invention provides a process for preparing a deinking agent comprising a compound represented by the general formula (Y) as defined above and having the value of OHV/(SV−AV+OHV) in the ranges of from 0 to 0.5 wherein hydroxyl value (OHV), saponification value (SV) and acid value (AV), comprising the step of esterifying an alkylene oxide adduct to a polyhydric alcohol having 3 to 10 valences with a carboxylic acid at a temperature of 100° C. to 260° C.

[0013] The weight average molecular weight referred to herein is a molecular weight relative to polystyrene standards, which is measured by gel permeation chromatography (GPC) under the following conditions:

[0014] Column: G4000 HXL+G2000 HXL (manufactured by Tosoh Corporation.),

[0015] Elution: THF (in 50 mmol/L CH₃COOH),

[0016] Flow rate: 1.0 mL/min,

[0017] Column temperature: 40° C.,

[0018] Detector: RI, and

[0019] Sample size: 5 mg/mL, 100 μL.

[0020] The OHV (hydroxyl value), the SV (saponification value) and the AV (acid value) are measured in accordance with the test methods described in JIS K 0070. Specifically, the OHV, the SV and the AV are measured by potentiometric titration (pyridine-acetic anhydride method), potentiometric titration, and potentiometric titration, respectively.

[0021] The compound represented by the general formula (a) is a mixture of compounds having ester bonds and obtained by adding, to glycerin or a mixture of glycerin and oil and fat as starting material, at least one alkylene oxide (referred to as AO hereinafter) selected from ethylene oxide (referred to as EO hereinafter), propylene oxide (referred to as PO hereinafter), and butylene oxide (referred to as BO hereinafter).

[0022] According to the present invention described above, provided is a deinking agent comprising an esterified reactant of a reaction product obtained by adding an alkylene oxide having 2 to 4 carbon atoms to glycerin or a mixture of glycerin and oil and fat, and a carboxylic acid, wherein its hydroxyl value (OHV), saponification value (SV) and acid value (AV) satisfy the following: OHV/(SV−AV+OHV) ranges from 0 to 0.3. The ratio of the compound represented by the general formula (Y) or (a) in the esterification reactants is preferably 809 or more, more preferably 90% or more by weight, and, in particular, the ratio of the compound having a weight average molecular weight of 2000 or more is preferably 80% or more, more preferably 90% or more by weight.

DETAILED DESCRIPTION OF THE INVENTION

[0023] The mechanism that the ink collecting property of the deinking agent of the present invention is good is unclear, but it appears that in the compound represented by the general formula (Y), or preferably (a), in the present invention, micelle structures by linked by AO chains are formed, and the structures contribute to improvement in ink collecting power, as will be described below.

[0024] In order to form the micelle structures linked by A chains, it is preferred that about R of the compound represented by the general formula (Y), preferably R¹, R² and R³ of the compound represented by the general formula (a), the ratio of acyl groups, which are hydrophobic groups, is large and the ratio of hydroxyl groups, which are hydrophilic groups, is small. In general, in the production of the compound represented by the general formula (Y), preferably (a), there is obtained a mixture of compounds having different numbers of hydroxyl groups or acyl groups and byproducts having a hydroxyl group, an acyl group and a carboxylic group. The OHV, the SV and the AV are indexes of the number of the hydroxyl groups, the total number of the acyl groups and the carboxylic groups and the number of the carboxylic groups, respectively. As an index of the capability of forming the micelle structures linked by AO chains, the ratio of the hydroxyl groups to the total of the acyl groups (SV−AV) and the hydroxyl groups (OHV), [OHV/(SV−AV+OHV)) can be used.

[0025] Namely about the compound represented by the general formula (Y) or the general formula (a) in the present invention and contained in the deinking agent wherein the ORV, the SV and the AV satisfy the following: OHV/(SV−AV+OHV) ranges from 0 to 0.3, or 0 to 0.5 in the specified production process, almost all of terminal OH groups of AO chains are substituted with hydrophobic groups. It is therefore considered that, when micelles are formed, one of the two hydrophobic groups of both terminals of the AO chain is taken in hydrophobic moieties of two adjacent micelles. Thus, the AO chain (EO/PO chain or the like) is shared between the hydrophobic groups so that a three-dimensional network structure of the micelles may be formed.

[0026] Herein, the ink collecting property is a performance such that ink particles dispersed by the deinking agent are adsorbed on generated bubbles and then float up. The adsorption strength of the dispersed ink particles on the bubbles depends on a hydrophobic bonding strength between the dispersed ink particles and the bubbles.

[0027] About the mechanism of improving the ink collecting power according to the present invention, the following two can be considered:

[0028] 1) In any (conventional) deinking agent that forms micelles which are not linked by AO chains, it is necessary that its hydrophobic groups adsorbed on ink particles are newly adsorbed on bubbles. However, in the deinking agent of the present invention, hydrophobic groups of micelles which are not adsorbed on ink particles, among micelle structures linked by AO chains, are adsorbed on bubbles and simultaneously ink particles linked by the AO chains are also entrained and adsorbed on this. Thus, the respective hydrophobic groups can independently fulfill their given functions.

[0029] 2) Since such structures are formed, it is difficult that the ink particles are entirely covered with the hydrophobic groups because of three-dimensional entanglement. It therefore appears that the fact that hydrophobic faces remains in the surfaces of the ink particles is also a factor for promoting adsorption onto the bubbles.

[0030] In the deinking agent of the present invention, the OHV/(SV−AV+OHY) is from 0 to 0.3, preferably from 0 to 0.2, and still more preferably from 0 to 0.1. If the OHV/(SV−AV+OHV) is 0.3 or less, the ink collecting power is improved. When compounds having a high OHV value, such as ethylene glycol, glycerin, a lower alcohol having 7 or less carbon atoms, and a low AO molecule added compound, as well as the compound represented by the general formula (Y) or the general formula (a) are added to the deinking agent, the OHV/(SV−AV+OHV) of fractions having a weight average molecular weight of 2000 or more is measured and satisfy the above-mentioned range in order to exclude any effect of the compounds which have a high OHV value and are added afterwards. The foaming property in the step of flotation is decreased so that the yield is improved. The more terminal OH groups of AO chains of the compound of the formula (Y) or (a) are substituted by hydrophobic groups, that is, the closer to zero the value of OHV/(SV−AV+OHV)becomes, the better improved is the compound as defined by the formula (Y) or (a) in collecting power of ink. It is a good deinking agent for a deinking system by which a low foaming is preferred in flotation.

[0031] The larger the value of OHV/(SV−AV+OHV) is from zero, on the other hand, the more increased foaming property the compound has. With an increased foaming property the yield rate of pulp is decreased. From the viewpoint of the yield rate of pulp, OHV/(SV−AV+OHV) is preferably not more than 0.5.

[0032] From the viewpoint of the foaming property and the yield rate of pulp, OHV/(SV−AV+OHV) ranges preferably from zero to 0.5, more preferably 0.1˜0.5, much more preferably 0.2˜0.5, especially preferably 0.3˜0.45. OHV /(SV−AV+OHV) is preferably 0.2˜0.45 in particularly for a deinking system in which a high foaming property is necessary in flotation and 0.1˜0.3 in particularly for a deinking system in which a low foaming property is necessary.

[0033] In production of the compound of the formula (Y) where an alkylene oxide adduct to a mixture of a polyhydric alcohol having 3 to 10 valences with fats and/or oils is esterified with a carboxylic acid, when an alkylene oxide is added to a mixture of the polyhydric alcohol with fats and/or oils, polyalkylene oxide adducts including no polyhydric alcohol is by-produced at the time of esterification or addition of the alkylene oxide. This by-product is poor in deinking. When an alkylene oxide adduct to a mixture of a polyhydric alcohol having 3 to 10 valences with fats and/or oils is used as a raw material for the esterification, OHV/(SV-AV+OHV) is preferably in the range of 0˜0.3.

[0034] When an alkylene oxide adduct to a polyhydric alcohol having 3 to 10 valences, not mixed with fats and/or oils, is used as a raw material for the esterification, little polyalkylene oxide adducts including no polyhydric alcohol is produced. When an alkylene oxide adduct to a polyhydric alcohol having 3 to 10 valences, not mixed with fats and/or oils, is used as a raw material for the esterification, OHV/(SV−AV+OHV)is preferably in the range of 0˜0.5.

[0035] The esterification temperature is preferably 100° C. to 260° C., more preferably 140° C. to 260° C., especially preferably 160° C. to 260° C., from the viewpoint of a reaction rate and prevention of cutting of the polyalkylene oxide chain. A suitalbe catalyst to the reaction temperature may be preferably used.

[0036] When a polyhydric alcohol having 3 to 10 valences or a mixture of a polyhydric alcohol having 3 to 10 valences with fats and/or oils is used as a raw material for the compound (Y) OHV/(SV−AV+OHV)is preferably in the range of 0˜0.3.

[0037] Particularly preferred is the OHV=0, namely, the terminal OH groups of AO are completely substituted with hydrophobic groups. It is however allowable that terminal OH groups are partially present.

[0038] The average number of the added AO molecules is from 45 to 1000, more preferably from 70 to 1000, still more preferably from 100 to 1000, and particularly preferably from 150 to 1000 per mole of the material to which the AO is to be added. The average number is most preferably from 150 to 600, considering the handling property. If the average number of the added AO molecules is 45 or more, linked micelles are construed to produce the advantageous effects of the present invention satisfactorily.

[0039] In the case that two or more (kind) AO are contained in the compound represented by the general formula (Y) or the general formula (a), about the addition form thereof a block polymerization chain or a random polymerization chain is allowable. The form is not particularly limited. Considering an appropriate bubble amount at the time of floatation, about the existence ratio (mole ratio) of EO in the AO the following is preferred: EO/AO=0.3 to 1. As the AO, EO and PO are preferably used together. About the mole ratio in this case, EO/PO=10/0 to 3/7 is preferred, and EO/PO=9/1 to 4/6 is more preferred.

[0040] R of the general formula (Y) and R¹ to R³ of the general formula (a) are each a hydrogen atom or an acyl group having 1 to 24 carbon atoms provided that at least one R¹ to R³ is an acyl group having 8 to 24 carbon atoms. More preferably, two or more thereof are acyl groups. These acyl groups may be unsaturated or saturated. The ratio of acyl groups having 8 to 24 carbon atoms, more preferably 12 to 24 carbon atoms in all groups of R and R¹ to R³ is preferably 80% or more by weight.

[0041] The content of the compound represented by the general formula (Y) or the general formula (a) in the deinking agent is preferably from 50 to 100% by weight, particularly preferably from 70 to 100% by weight.

[0042] The compound represented by the general formula (Y) or the general formula (a) can be obtained by esterifying a reaction product wherein the AO is added to glycerin or a mixture of glycerin and oil and fat with a carboxylic acid. The OHV/(SV−AV+OHV) can be adjusted by setting a target value of the AV in light of the mole ratio between charging ingredients, picking up a sample and measuring the AV.

[0043] The compound represented by the general formula (a) is also present in a known reaction product wherein an AO is added to a mixture of oil and fat and an alcohol. However, according to this reaction, by-products such as an AO copolymer besides the compound represented by the general formula (a) are produced if they are caused to react in accordance with a formulation described, for example, in Japanese Patent No. 1573380. For this reason, the value of the OHV becomes large so that the OHV/(SV+OHV−AV) of the whole of the mixture becomes larger than 0.3.

[0044] As the carboxylic acid used in the production of the compound represented by the general formula (Y) or the general formula (a), a carboxylic acid having 8 to 24 is used. Specific examples thereof include lauric acid, stearic acid, and oleic acid. If necessary, a carboxylic acid having 1 to7 carbon atoms can be used together.

[0045] The deinking agent of the present invention can be used together with a known deinking agent, for example, a higher-alcohol AO-added product, an aliphatic acid AO-added product, an AO-added product of a mixture of oil and fat and an alcohol, an AO-added product of a mixture of a polyhydric carboxylic acid and an alcohol. The deinking agent of the present invention may be used together with, for example, a higher aliphatic acid, a higher aliphatic acid salt, or the like in order to raise the yield of deinked pulp, and the agent may be used together with sulfate of a higher-alcohol, a polyhydric alcohol such as glycerin, and AO-added products thereof, considering improvement in runnability, such as control of foaming property and antifoaming property in the step of floatation.

[0046] Even if the deinking agent of the present invention is added in any step before the step of floatation, higher-quality deinked pulp can be obtained. In general, the deinking agent of the present invention is added in any one of pulping, mixing and flotation steps or in all the steps. The adding amount thereof is not particularly limited, and is preferably from 0.03 to 1.0% by weight of starting waste paper.

[0047] The deinking agent of the present invention makes it possible to improve the ink collecting power in the step of flotation and yield high-quality deinked pulp without lowering the yield of pulp.

EXAMPLES Production Example 1-1

[0048] To a 2-liter autoclave were charged 230.3 g of glycerin and 16.8 g of 100% KOH, and then the mixture was heated up to a temperature of 135° C at a stirring rate of about 600 rpm. Next, the reaction mixture was caused to react with 1753 g of a mixture wherein the mole ratio between EO and PO was 228:102 (10 moles of EO and 4.5 moles of PO corresponding to one mole of glycerin). About reaction conditions at this time, the temperature was 135° C. and the pressure was from 1 to 3 kg/cm² (98 to 294 kPa) (gauge pressure). After the end of the reaction, the temperature was cooled to 80° C. to yield an intermediate synthesis product 1 (reactant wherein 10 moles of EO and 4.5 moles of PO corresponded to one mole of glycerin).

[0049] Next, 290 g of the intermediate synthesis product 1 was charged into a 2-liter autoclave, and then the mixture was heated up to a temperature of 135° C. at a stirring rate of about 600 rpm. The resultant was then caused to react with 1678 g of a mixture wherein the mole ratio between EO and PO was 228:102. About reaction conditions at this time, the temperature was 135° C. and the pressure was from 1 to 3 kg/cm² (98 to 294 kPa) (gauge pressure). After the end of the reaction, the temperature was cooled to 80° C. to yield an intermediate synthesis product 2 of AV=−1.1, OHV=35.7 and SV=−1.1 (reactant wherein 76 moles of EO and 34 moles of PO corresponded to one mole of glycerin).

[0050] Next, to a 200-mL four-neck flask were charged 124.4 g of the resultant intermediate synthesis product 2 and 26.3 g of stearic acid (AV=202.7) in such a manner that the mole ratio between the two (the reaction ratio (a)/(b)), which was calculated from the OHV of the intermediate synthesis product 2 and the AV of stearic acid, would be 1:1.2. The mixture was caused to react at 215° C. under introduced and sealed nitrogen for 8 hours to yield a synthesis product (the present invention product 7 of Table 1) wherein AV=6.5, OHV=2.8, SV=34.7 and the OHV/(SV−AV+OHV) was 0.09.

Production Example 1-2

[0051] To a 2-liter autoclave was charged 668 g of the intermediate synthesis product 2 synthesized in Production Example 1-1, and then the mixture was heated up to a temperature of 135° C. at a stirring rate of about 600 rpm. The resultant was then caused to react with 1311 g of a mixture wherein the mole ratio between EO and PO was 228:102. About reaction conditions at this time, the temperature was 135° C. and the pressure was from 1 to 3 kg/cm² (98 to 294 kPa) (gauge pressure). After the end of the reaction, the temperature was cooled to 80° C. to yield an intermediate synthesis product 3 of AV=−0.3, OHV=16.3 and SV=−0.38 (reactant wherein 228 moles of EO and 102 moles of PO corresponded to one mole of glycerin).

[0052] Next, to a 200-mL four-neck flask were charged 136.8 g of the resultant intermediate synthesis product 3 and 13.2 g of stearic acid (AV=202.7) in such a manner that the mole ratio between the two, which was calculated from the OHV of the intermediate synthesis product 3 and the AV of stearic acid, would be 1:1.2. The mixture was caused to react at 215° C. under introduced and sealed nitrogen for 8 hours to yield a synthesis product (No. 1 of Table 1) wherein AV=2.3, OHV=0.7, SV=17.8 and the OHV/(SV−AV+OHV) was 0.04.

Production Example 1-3

[0053] To a 2-liter autoclave were charged 151.1 g of tallow, 4.8 g of glycerin (0.3 mole of glycerin per mole of tallow) and 1.2 g of 100% KOH, and then the mixture was heated up to a temperature of 135° C. at a stirring rate of about 600 rpm. Next, the reaction mixture was caused to react with 1834.4 g of a mixture wherein the mole ratio between EO and PO was 148:66 (148 moles of EO and 66 moles of PO corresponding to one mole of tallow). About reaction conditions at this time, the temperature was 135° C. and the pressure was from 1 to 3 kg/cm² (98 to 294 kPa) (gauge pressure). After the end of the reaction, the temperature was cooled to 80° C. to yield a synthesis product (reactant wherein 148 moles of EO and 66 moles of PO corresponded to one mole of tallow, No. 17 of Table 1) wherein AV=0.52, OHV=18.9, SV=16.7 and the OHV/(SV−AV+OHV) was 0.54.

Production Example 1-4

[0054] To a 200-mL four-neck flask were charged 134.9 g of the synthesis product synthesized in Production Example 1-3 and 15.1 g of stearic acid (AV=202.7) in such a manner that the mole ratio between the two, which was calculated from the OHV of the synthesis product and the AV of stearic acid, would be 1:1.2. The mixture was caused to react at 215° C. under introduced and sealed nitrogen for 8 hours to yield a synthesis product (No. 14 of Table 1) wherein OHV=0, and the OHV/(SV−AV+OHV) was 0.

[0055] No. 18 of Table 1 was synthesized in the same manner as in Production Example 1-3. About Nos. 2 to 6 and 8 to 13, and Nos. 15 and 16, an AO was added to glycerin in the same manner as in Production Example 1-1 or 1-2 to synthesize, as an intermediate product, a compound before esterifying reaction, and next this intermediate product and a carboxylic acid were charged to conduct esterification. TABLE 1 Intermediate synthesis product (a) Deinking Average number of Average number of Carboxylic (a)/(b) OHV/(SV + agent Starting compound added moles of EO/PO added moles of AO acid(b) reaction ratio*¹ OHV − AV)*³ 1 Glycerin EO228/PO102 330 Stearic acid 1/1.2 0.04 2 Glycerin EO228/PO102 330 Stearic acid 1/1.2 0.12 3 Glycerin EO228/PO102 330 Stearic acid 1/0.8 0.22 4 Glycerin EO276/PO124 400 Stearic acid 1/1.2 0.11 5 Glycerin EO154/PO68 220 Stearic acid 1/1.2 0.11 6 Glycerin EO114/PO51 165 Stearic acid 1/1.2 0.11 7 Glycerin EO76/PO34 110 Stearic acid 1/1.2 0.09 8 Glycerin EO54/PO24  78 Stearic acid 1/1.2 0.08 9 Glycerin EO38/PO17  55 Stearic acid 1/1.2 0.07 10 Glycerin EO264/PO66 330 Stearic acid 1/1.2 0.03 11 Glycerin EO165/PO165 330 Stearic acid 1/1.2 0.02 12 Glycerin EO228/PO102 330 Lauric acid 1/1.2 0.01 13 Glycerin EO228/PO102 330 Oleic acid 1/1.2 0.03 14 Tallow/glycerin EO148/PO66   165*² Stearic acid 1/1.2 0.00 (molar ratio: 1/0.3) 15 Glycerin EO228/PO102 330 Stearic acid 1/0.5 0.52 16 Glycerin EO28/PO12  40 Stearic acid 1/1.2 0.07 17 Tallow/glycerin EO148/PO66   165*² — — 0.54 (molar ratio: 1/0.3) 18 Tallow/glycerin EO54/PO27   62*² — — 0.37 (molar ratio: 1/0.3) 19 Higher alcohol AO-added product[DI-767, manufactured by KAO Corp.] —

Example 1

[0056] The deinking agents of Table 1 were used to conduct ink removing treatment and evaluate ink removing performances thereof in accordance with the following steps. The results are shown in Table 2

Ink Removing Treatment

[0057] Waste paper collected in a city (starting materials) was deteriorated at 80° C. for 5 hours, and cut into 2 cm×5 cm sizes. Thereafter, a given amount thereof was put into a desk disintegrating machine, and thereto were added hot water, sodium hydroxide in an amount of 0.5% by weight (of the starting materials) and each of the deinking agents in an amount of 0.39 by weight (of the staring materials). The mixture was subjected to disintegrating treatment at a pulp concentration of 4% by weight and at 45° C. and 3000 rpm for 10 minutes. Next, the pulp slurry was concentrated up to a pulp concentration of 17% by weight. Thereto were added sodium hydroxide in an amount of 1.0% by weight (of the starting materials), sodium silicate No. 3 in an amount of 2.0% by weight (of the starting materials), hydrogen peroxide in an amount of 0.3% by weight (of the starting materials), and hot water, so as to set the pulp concentration to 15% by weight. In a high temperature water tank of 55° C. temperature, the solution was subjected to bleaching treatment for 2 hours. The pulp slurry was diluted with hot water to a concentration of 1.0% by weight. Thereafter, the slurry was subjected to flotation treatment at 40° C. for 6 minutes (using a flotater manufactured by Kyokuto Shinko Co., Ltd.).

[0058] To the pulp slurry subjected to the flotation was added aluminum sulfate in an amount of 10% by weight of the pulp. After the slurry was stirred, a 150-mesh wire with a 109 μm mesh was used to produce a handmade sheet (ink-removed sheet) having a basis weight of 150 g/m² according to JIS P8209.

[0059] The pulp slurry obtained by the ink removing treatment was concentrated with a #80 mesh wire with a 180 μm mesh so as to have a pulp concentration of 10% by weight. Tap water was used to perform diluting-operation 3 times up to a pulp concentration of 1% by weight. Thereafter, as completely washed pulp slurry, aluminum sulfate in an amount of 10% by weight of the pulp was added, and the resultant was stirred. A 150-mesh wire with a 109 μm mesh was then used to produce a handmade sheet (completely washed sheet) having a basis weight of 150 g/m² according to JIS P8209.

Ink Removing Performance (1) Brightness

[0060] About the above-mentioned ink-removed sheet, SPECTRO COLOR METER PF-10 (MGO standard) manufactured by Nippon Denshoku Industries Co., Ltd. was used to measure the brightness by Hunter. The average of values of the front and back surfaces was obtained. A significant difference in the brightness was 0.5% or more in the present example.

(2) Ink Collecting Property

[0061] About the above-mentioned ink-removed sheet and completely washed sheet, ERIC 950 manufactured by Technidyne Corporation was used to measure the remaining ink effect concentrations. As an index of the ink collecting property, a difference between the remaining ink effect concentration (I) of the completely washed sheet and the remaining ink effect concentration (II) of the ink-removed sheet was used to make evaluation. As the difference is smaller, the ink collecting property is higher. A significant difference is 20 ppm.

(3) Pulp Yield

[0062] A difference between the weight (A) of the pulp before the ink removing treatment and the weight (B) of the pulp discharged from the upper of the flotater, in the above-mentioned ink removing treatment, was divided by the weight (A) of the pulp before the ink removing treatment, and the resultant value was multiplied by 100 (that is, ((A)−(B)]÷(A)×100]. The resultant value was defined as the pulp yield (%). A significant difference was 0.5% or more in the present example. TABLE 2 Ink collecting property Remaining ink amount(ppm) Difference of Test No. Brightness Completely washed sheet the (II) from the Pulp yield of table I (%) (I) Ink-removed sheet (II) (I) (%) 1 50.6 316 644 328 90.7 2 50.1 304 645 341 90.5 3 49.5 310 666 356 90.2 4 50.2 306 638 332 90.2 5 49.9 310 671 361 90.9 6 49.6 305 689 384 91.5 7 49.0 319 732 413 92.2 8 48.8 321 742 421 92.7 9 48.5 318 749 431 93.0 10 50.7 318 639 321 90.2 11 49.7 311 684 373 91.5 12 49.3 324 707 383 90.2 13 49.5 318 698 380 90.3 14 49.3 319 702 383 91.3 20*1 49.7 301 661 360 91.0 21*2 49.6 308 661 353 90.4 15 49.4 321 677 356 86.8 16 47.4 307 873 566 94.8 17 49.3 331 685 354 86.4 18 47.5 329 817 488 90.5 19 47.8 322 786 464 90.5

Production Example 2-1

[0063] To a 2-liter autoclave were charged 250.0 g of glycerin and 18.3 g of 100% KOH and then the mixture was heated up to a temperature of 135° C. at a stirring rate of about 600 rpm. Next, the reaction mixture was caused to react with 1416 g of a mixture wherein the mole ratio between EO and PO was 210:90, corresponding to 7.5 moles of EO and 3.2 moles of PO to one mole of glycerin. About reaction conditions at this time, the temperature was 135° C. and the pressure was from 1 to 3 kg/cm² (98 to 294 kPa) (gaugepressure). After the end of the reaction, the mixture was cooled to 80° C. 1434.3 g having been taken out of the autoclave, 250 g remained in the autoclave. The intermediate product of 250 g was, in the autoclave, heated up to 135° C. at a stirring rate of about 600 rpm and reacted with 1416 g of a mixture of EP an PO at the mole ratio EP/PO of 210 to 90. About reaction conditions at this time, the temperature was 135° C. and the pressure was from 1 to 3 kg/cm² (98 to 294 kPa) (gauge pressure). After the end of the reaction, the mixture was cooled to 80° C. 1166 g having been taken out of the autoclave, 500 g remained in the autoclave. The intermediate product of 500 g, corresponding to 58.7 moles of EO and 25.1 moles of PO to one mole of glycerin, was, in the autoclave, heated up to 135° C. at a stirring rate of about 600 rpm and reacted with 1264 g of a mixture of EP an PO at the mole ratio EP/PO of 210 to 90. The reaction conditions were the temperature of 135° C. and the pressure of 1 to 3 kg/cm² (98 to 294 kPa) (gauge pressure). After the end of the reaction, the mixture was cooled to 80° C. obtain a reaction product (a1) of AV=−0.13, OHV=15.2 and SV<1.

[0064] Next, to a one liter four-neck flask were charged 905.9 g of the resultant reaction product (al) and 88.3 g of stearic acid (AV=202.7) in such a manner that the mole ratio between the two (the reaction ratio (a)/(b)), which were calculated from the OHV of the reaction product (a1) and the AV of stearic acid (b1), would be 1:1.3. 0.5 wt.% (5.0 g), per the total of the fed reactants, of dibutyl tin oxide as a catalyst was fed and the mixture was reacted for esterification at 225° C.±5° C. with nitrogen gas blown in.

[0065] The synthesis product (No. 1 of Table 3) was obtained by the4 hour reaction with AV=5.7, OHV=3.2, SV=18.4 and OHV/(SV−AV+OHV) of 0.20.

[0066] The synthesis product (No. 2 of Table 3) was obtained by the 5 hour reaction with AV=5.2, OHV=2.7, SV=18.4 and OHV/(SV−AV+OHV) of 0.17.

[0067] The synthesis product (No. 3 of Table 3) was obtained by the 6 hour reaction with AV=4.2, OHV=1.2, SV=18.3 and OHV/(SV−AV+OHV) of 0.08.

Production Example 2-2

[0068] To a one liter four-neck flask were charged 321.8 g of the reaction product (a1) and 28.9 g of stearic acid (AV=202.7) in such a manner that the mole ratio between the two (the reaction ratio (a)/(b)), which were calculated from the OHV of the reaction product (a1) and the AV of stearic acid (b1), would be 1.2. 0.5 wt. % (1.8 g), per the total of the fed reactants, of dibutyl tin oxide as a catalyst was fed and the mixture was reacted for esterification at 215° C.±5° C. with nitrogen gas blown in.

[0069] The synthesis product (No. 4 of Table 3) was obtained by the 4 hour reaction with AV=8.5, OHV=6.3, SV=17.4 and OHV/(SV−AV+OHV) of 0.41.

[0070] The synthesis product (No. 5 of Table 3) was obtained by the 5 hour reaction with AV=7.6, OHV=5.4, SV=17.5 and OHV/(SV−AV+OHV) of 0.35.

Production Example 2-3

[0071] To a 2-liter autoclave were charged 244.2 g of tallow, 5.3 g of glycerin (0.2 mole of glycerin per mole of tallow) and 3.6 g of 100% KOH and then the mixture was heated up to a temperature of 135° C. at a stirring rate of about 600 rpm. Next, the reaction mixture was reacted with 1604 g of a mixture of EP and PO having the mole ratio between EO and PO of 206:83, corresponding to 69 moles of EO and 28 moles of PO to one mole of glycerin structure. The reaction conditions at this time were the temperature of 135° C. and the pressure of 1 to 3 kg/cm² (98 to 294 kPa) (gauge pressure). After the end of the reaction, the mixture was cooled to 80° C. 1396 g having been taken out of the autoclave, 460 g remained in the autoclave. The intermediate product of 460 g was, in the autoclave, heated up to 135t with at a stirring rate of about 600 rpm and reacted with 786 g of a mixture of EP an PO at the mole ratio EP/PO of 206 to 83. The reaction conditions were the temperature of 135° C. and the pressure of 1 to 3 kg/cm² (98 to 294 kPa) (gauge pressure). After the end of the reaction, the mixture was cooled to 80° C. to obtain a reaction product (No. 19 of Table 3) having AV=0.06, OHV=13.8, SV=8.4 and OHV/(SV−AV+OHV) of 0.62, corresponding to 206 moles of EO and 83 moles of PO to one mole of glycerin structure.

Production Example 2-4

[0072] To a 200 milliliter four-neck flask were charged 148.0 q of the reaction product (a1) and 22.2 g of stearic acid (AV=202.7) in such a manner that the mole ratio between the two (the reaction ratio (a)/(b)), which were calculated from the OHV of the reaction product (a1) and the AV of stearic acid (b1), would be 1/2. 0.5 wt. % (0.86 g), per the total of the fed reactants, of dibutyl tin oxide as a catalyst was fed and the mixture was reacted for esterification at 215° C.±5° C. with nitrogen gas blown in. The synthesis product was obtained with AV=14.8, OFV=2.8, SV=26.0 and OHV/(SV−AV+OHV) of 0.20. Out of this was distilled out stearic acid in vacuum at 5.2 kPa. The synthesis product (No. 6 of Table 3) was obtained with AV=4.3, OHV=3.0, SV=16.3 and OHV/(SV−AV+OHV) of 0.20.

Production Example 2-5

[0073] To a 200 milliliter four-neck flask were charged 145.4 g of the reaction product (a1) and 13.1 g of stearic acid (AV=202.7) in such a manner that the mole ratio between the two (the reaction ratio (a)/(b)), which were calculated from the OHV of the reaction product (a1) and the AV of stearic acid (b1), would be 1/1.2. 0.5 wt. % (0.8 g), per the total of the fed reactants, of dibutyl tin oxide as a catalyst was fed and the mixture was reacted for esterification at 280° C.±5° C. with nitrogen gas blown in. The synthesis product (No. 20 of Table 3) was obtained with AV=1.1, OHV=2.9, SV=17.4, OHV/(SV−AV+OHV) of 0.15, (SV**−AV**+OHV**) of 19.2, (SV*−AV*+OHV*) of 14.1 and (SV**−AV**+OHV**)/(SV*−AV*+OHV*) of 1.36. SV**, AV**, OHV**, SV*, AV* and OHV* are defined as follows: SV*, AV* and OHV* are ideal values of SV, AV and OHV, respectively, after the reaction where one of (a) and (b) which is fed in the smaller moles than the other, has been completely consumed. SV**, AV** and OHV** are ideal values of SV, AV and OHV, respectively, after the reaction has finished. As part of polyalkylenen oxide chains vaporizes in broken polyalkylenen oxide, (SV**−AV**+OHV**)/(SV*−AV*+OHV*) is getting larger. This is the reason the deinking agent of the invention is involved in such a difficulty. The value of (SV**−AV**+OHV**)/(SV*−AV*+OHV*) is preferably smaller than 1.25.

Production Example 2-6

[0074] No. 7 of Table 3 was obtained in the same way as Production Example 2-1 except that the reaction product (a1) and stearic acid (AV=202.7) were fed in such a manner that the mole ratio between the two (the reaction ratio (a)/(b)), which were calculated from the OHV of the reaction product (a1) and the AV of stearic acid (b1), may be the same as the reaction rate shown in the table and esterification was effected at 250° C.±5° C. with nitrogen gas blown in for 3 hours.

Production Example 2-7

[0075] Nos. 8 to 18, 22 and 23 of Table 3 was obtained by esterification in the same way as Production Example 2-1 except that the reaction product (a) was prepared in the same way as Production Example 2-1 and the reaction product (a) and a carboxylic acid (b) were fed at the reaction rate of (a)/(b) shown in the table.

[0076] No. 21 of Table 3 was obtained by mixing uniformly the reactants in the way where the mole ratio between the reaction product (a1) and stearic acid (AV=202,7), which were calculated from the OHV of the reaction product (a1) and the AV of stearic acid (b1), may be 1/1.3.

Example 2

[0077] Deinking was effected with deinking agents of Table 3 in the same way as the deinking treatment of Example 1. Deinking performance was evaluated. Results are shown of Table 4. The flotation was effected with MT Flotator of Ishikawajima Sangyo Kikai Co., Ltd.

[0078] In evaluation of deinking agents, the pulp yield depends on foaming of the deinking agent. In addition, whiteness and ink collection greatly depend on the pulp yield. That is, the smaller the pulp yield is, the higher the whiteness and the ink collection are. Among various deinking methods, some require a low foaming deinking agent, but some require a high foaming deinking agent. This is the reason the deinking effect can be difficultly compared between different pulp yields in terms of whiteness and ink collection. In the invention, the deinking effect is evaluated at a given pulp yield in terms of whiteness and ink collection, that is, a deinking efficiency. The evaluation is carried out at an added percentage of the deinking agent of 0.3 %. In No. 24 and No.25 a known ink removing agent was used in an amount of 0.2 wt. % and 0.3 wt. %, respectively, to the starting material.

[0079] Supposing a curve of the invention and another curve of No. 24 to 25, plotting pulp yields at the X axis and whiteness at the Y axis, starting at the pulp yield (100%) and whiteness before deinking, it is not considered that the two curves cross each other. This is the reason the deinking agent of the invention has a high deinking efficiency. NO. 20 is inferior to the invention in view of deinking and is found to promote blacking. Then it is not good at handling. TABLE 3 Reaction product (a) EO/PO AO Average Average OHV/ Esterification Deinking number number (a)/(b) (SV − Reaction Reaction agent Material of moles of moles Carboxylic Reaction AV + temperature time Test No. compound added added acid (b) rate*1 OHV)*3 ° C. Hour 1 Production (a1) Glycerin EO210/PO90 300 (b1) Stearic acid 0.77 0.20 225 4 example2-1 2 ↑ ↑ Glycerin EO210/PO90 300 ↑ Stearic acid 0.77 0.17 225 5 3 ↑ ↑ Glycerin EO210/PO90 300 ↑ Stearic acid 0.77 0.08 225 6 4 Production ↑ Glycerin EO210/PO90 300 ↑ Stearic acid 0.77 0.41 215 4 example2-2 5 ↑ ↑ Glycerin EO210/PO90 300 ↑ Stearic acid 0.77 0.35 215 5 6 Production ↑ Glycerin EO210/PO90 300 ↑ Stearic acid 0.50 0.20 215 3 example2-4 7 Production ↑ Glycerin EO210/PO90 300 ↑ Stearic acid 0.83 0.12 250 3 example2-6 8 Production (a2) Glycerin EO228/PO102 330 ↑ Stearic acid 1.25 0.22 215 8 example2-7 9 ↑ (a3) Glycerin EO276/PO124 400 ↑ Stearic acid 0.83 0.33 215 5 10 ↑ (a4) Glycerin EO154/PO68 220 ↑ Stearic acid 0.83 0.25 215 6 11 ↑ (a5) Glycerin EO114/PO51 165 ↑ Stearic acid 0.83 0.21 215 7 12 ↑ (a6) Glycerin EO76/PO34 110 ↑ Stearic acid 0.83 0.15 215 8 13 ↑ (a7) Glycerin EO54/PO24  78 ↑ Stearic acid 0.83 0.18 215 7 14 ↑ (a8) Glycerin EO38/PO17  55 ↑ Stearic acid 0.83 0.07 215 8 15 ↑ (a9) Glycerin EO264/PO66 330 ↑ Stearic acid 0.83 0.37 215 5 16 ↑ (a10) Glycerin EO165/PO165 330 ↑ Stearic acid 0.83 0.48 215 3 17 ↑ (a11) Glycerin EO228/PO102 330 (b2) Lauric acid 0.83 0.29 215 5 18 ↑ (a12) Glycerin EO228/PO102 330 (b3) Oleic acid 0.83 0.36 215 4 19 Production Tallow/ EO206/PO83   240*2 (b1) Stearic acid — 0.62 — — example2-3 glycerin(1/0.2) 20 Production (a1) Glycerin EO210/PO90 300 ↑ Stearic acid 0.83 0.15 280 1.5 example2-5 21 (a1) Glycerin EO210/PO90 300 ↑ Stearic acid 0.77 1.00 — 0 22 Prouction (a13) Glycerin EO28/PO12  40 (b1) Stearic acid 0.83 0.34 215 6 example2-7 23 ↑ (a14) Ethylene EO210/PO90 300 ↑ Stearic acid 0.83 0.20 215 5 glycohol 24 DI-767 (higher aocoholAO adduct, produced by Kao co.) 25 DI-767 (higher alcoholAO adduct, produced by Kao Co.)

[0080] TABLE 4 Deinking Deinking Ink collecting property agent agent Remaining ink amount (ppm) Test No. addition Whiteness Completely Deinking (II) − (I) Pulp yield of Table 3 ratio (%) (%) washed sheet (I) treatment sheet (II) difference (%) 1 0.3 47.7 302 810 508 83.9 2 0.3 46.9 298 958 660 89.1 3 0.3 45.9 302 1049 747 91.8 4 0.3 48.1 307 788 481 78.7 5 0.3 48.5 297 760 463 80.5 6 0.3 47.7 303 811 508 85.3 7 0.3 46.3 307 1027 720 89.4 8 0.3 47.9 296 791 495 84.7 9 0.3 48.4 298 767 469 82.5 10 0.3 48.1 301 789 488 83.4 11 0.3 47.8 299 814 515 86.0 12 0.3 48.5 302 1004 702 89.8 13 0.3 46.9 302 947 645 87.3 14 0.3 45.9 310 1050 740 90.8 15 0.3 48.4 312 779 467 78.8 16 0.3 48.0 307 790 483 77.4 17 0.3 47.6 305 823 518 82.2 18 0.3 47.8 292 795 503 80.6 19 0.3 46.9 311 973 662 73.1 20 0.3 46.2 302 992 690 86.6 21 0.3 46.6 297 981 684 72.0 22 0.3 46.6 304 978 674 82.3 23 0.3 46.7 303 918 615 82.1 24 0.3 47.3 328 845 517 77.1 25 0.2 46.9 317 887 570 80.3 

1. A deinking agent comprising a compound represented by the following general formula (Y), its hydroxyl value (OHV), saponification value (SV) and acid value (AV) satisfying the following: OHV/(SV−AV+OHV) ranges from 0 to 0.3. X—[O(AO)m-R]n   (Y) [wherein r is each independently a hydrogen atom or an acyl group having 1 to 24 carbon atoms, provided that at least one of plural r is an acyl group having 8 to 24 carbon atoms, a is an alkylene group having 2 to 4 carbon atoms, a may be the groups wherein the numbers of their carbon atoms are different, and m×n is a numerical number of from 45 to 1000, X is a polyhydric alcohol group, n is a number of 3 to 10 being equivalent the valence of X.
 2. The deinking agent according to claim 1, in which the compound is represented by the following general formula (a), its hydroxyl value (OHV), saponification value (SV) and acid value (AV) satisfying the following: OHV/(SV−AV°OHV) ranges from 0 to 0.3,

wherein R¹ to R³ are each independently a hydrogen atom, or an acyl group having 1 to 24 carbon atoms provided that at least one of R¹ to R³ is an acyl group having 8 to 24 carbon atoms, A is an alkylene group having 2 to 4 carbon atoms, A may be the groups wherein the numbers of their carbon atoms are different, and a+b+c is a numerical number of from 45 to
 1000. 3. The deinking agent according to claim 2, in which the hydroxyl value (OHV) of a fraction having a weight average molecular weight of 2000 or more, the saponification value (SV) thereof and the acid value (AV) thereof satisfying the following: OHV/(SV−AV+OHV) ranges from 0 to 0.3.
 4. The deinking agent according to claim 2, wherein the compound represented by the general formula (a) is an esterified reactant of a reaction product obtained by adding an alkylene oxide to glycerin or a mixture of glycerin and oil and fat, and a carboxylic acid.
 5. A method of removing ink by using the deinking agent according to any one of claim 1 or 2 in an ink removing step.
 6. A process for preparing a deinking agent comprising a compound represented by the general formula (Y) as defined in Claim land having the value of OHV/(SV−AV+OHV) in the ranges of from 0 to 0.3 wherein hydroxyl value (OHV), saponification value (SV) and acid value (AV), comprising the step of esterifying an alkylene oxide adduct to a trihydric alcohol or a mixture of a trihydric alcohol with fats and/or oils with a carboxylic acid at a temperature of 100° C. to 260° C.
 7. A process for preparing a deinking agent comprising a compound represented by the general formula (Y) as defined in claim 1 and having the value of OHV/(SV−AV+OHV) in the ranges of from 0 to 0.5 wherein hydroxyl value (OHV) saponification value (SV) and acid value (AV), comprising the step of esterifying an alkylene oxide adduct to a trihydric alcohol with a carboxylic acid at a temperature of 100° C. to 260° C.
 8. A deinking agent obtained by the process as defined in claim
 7. 